Problems w/ BIOS, Startup, and random restarts

I had issues with starting my home built comp last year when I first built it, after fixing a disfunctional RAM stick.

The computer would start, show the logo screen, start loading windows, then the screen went blank and the power light on the monitor flashes orange.

Now, pretty much out of nowhere it's started freezing, I get error messages that my graphics driver has failed, then when I try to startup again, the logo screen looks all chopped up (not displayed right - parts are cut out).

On top of that, when it goes to the black screen w/ white text checking up on all my devices and such, it seems to not read them correctly and has apostrophes all over the place.
My keyboard is not being detected, so I can't select the safe mode option when it asks how I want to startup, so it auto selects 'run windows normally', then after a few seconds of attempting to start windows, auto-restarts again.

I don't understand why this would start happening all of a sudden, nor did I ever figure out why the problem existed when I first built the machine.

The only change that took place when this error started happening was my installing a game, which I just uninstalled in safe mode. No change (except keyboard now being undetected).

Appears the problem could be with my CPU, motherboard, video card or hard drive. RAM should be fine since I ran a memtest on it before when this was happening and it showed fine. Power supply should be fine since I've tried two different ones, no change.


Ideas on what this is about or what I can do would be appreciated.